OP, I'll spare you the bs a lot of others are giving: big boobs > small boobs.
You're misunderstanding this though, I think. Small boobs are not unattractive, they're just not necessarily attractive; they're neutral, if you like. People have lots of different features that make them attractive, and big boobs are just one of them. Features aren't all physical either, who you are counts for something!
I'll tell you what is an unattractive feature though, insecurity. Fake boobs might pass for real ones under your clothes, but I'd be really disappointed if I saw them after getting to know you. I don't think you'll magically feel confident after getting them anyway, you already rubbished every other aspect of yourself.
I know it's hard but just learn to accept yourself. I bet you're much more attractive than you make out.